Automatic Peritoneal Dialysis (APD) machines have been around for a number of years. The introduction of these APD machines helped to advance peritoneal dialysis modality. There are two major types of APD machines The most complicated versions are the Automatic Fluid Proportioning units. Because of their large size and the operational complexities these machines are gradually being phased out of clinical use.
The less complex APD machines are the cyclers. Functionally most of the cyclers have five independent levels or fluid stages. By gravity, dialysate (dialysis solution) is sequentially passed from one level to another.
The dialysate originates from the first, highest stage which holds the fresh sterile solution bulk. From there the dialysate is transferred to the second, next lower stage where the solution is measured and heated. The next lower stage (third) is the patient. He/she receives the measured solution from the second stage. The fourth stage is the drain bag used to collect the spent dialysate from the patient. The final, lowest stage receives the waste dialysate from the drain bag.
One variation of the cycler fluid level arrangement is where the first stage is located below the second stage and dialysate is transferred from the first stage to the second stage by means of a pump. All cyclers otherwise work according to the same general principle: they accommodate 4 to 12 bags of prepared sterile dialysate, select a predetermined volume of solution from the "bulk" solution bags, heat the dialysate up to near body temperature and deliver this solution to the patient. After a preset time (dwell time), the dialysate is drained out of the patient and into a drain bag were it is weighed. The spent dialysate is discarded from the drain bag into a final drain which could be a waste bag. Typical prior art cycler machines are represented by Agarwal et al U.S. Pat. No. 4,096,859, Lasker et al U.S. Pat. No. 3,872,863 and Davis et al U.S. Pat. No. 4,585,436.
The major forms of peritoneal dialysis (PD) therapy are
1) The Manual Peritoneal Dialysis PA1 2) The Continuous Ambulatory Peritoneal Dialysis (CAPD) PA1 3) The Intermittent Peritoneal Dialysis (IPD) PA1 4) The Continuous Cyclic Peritoneal Dialysis (CCPD). PA1 (1) a manifold, PA1 (2) a receptacle for waste dialysate, PA1 (3) a plurality of fresh dialysate bags, PA1 (4) support means supporting said plurality of fresh dialysate bags, PA1 (5) heating means for heating said dialysate bags on said support means, PA1 (6) a first conduit for connecting the manifold with the patient catheter, PA1 (7) a second conduit for connecting said manifold with said receptacle, PA1 (8) at least two further conduits connecting the manifold individually with each of said fresh dialysate bags, PA1 (9) clamping means for selectively closing at least said second and said further conduits, and PA1 (10) electronic control means for controlling said clamping means, the electronic control means having an automatic mode in which the control means causes the apparatus to cycle through the following phases: PA1 said steps a) and b) repeating for another fresh dialysate bag, and so on until all such bags have been used; PA1 (11) safety means for determining whether a sufficient quantity of dialysate has drained from the patient's peritoneum cavity during the drain phase, and for passing such information to said electronic control means, said electronic control means being such as not to advance to the next fill/dwell phase if an insufficient quantity of dialysate has drained, and PA1 (12) selection means allowing a user to select the first and second predetermined times. PA1 a) providing an apparatus which includes PA1 b) using electronic control means for controlling said clamping means in an automatic mode in which the control means causes the apparatus to cycle through the following phases: PA1 c) determining whether a sufficient quantity of dialysate has drained from the patient's cavity during the drain phase, and passing such information to said electronic control means, the electronic control means being such as not to advance to the next fill/dwell phase if an insufficient quantity of dialysate has drained, and PA1 d) repeating said steps 1) and 2) for another fresh dialysate bag, and so on until all such bags have been used.
Therapies 1 and 2 are performed without the need of a machine. The contents of the solution bags are individually and manually delivered to the patient and then drained from the patient accordingly. Therapies 3 and 4 require the use of a cycler. The contents of more than one solution bag are mixed together before delivery to the patient. Of all the PD therapies the most popular one is the CAPD. It is used mainly by patients who have been trained to perform their treatments at their respective homes.
Originally, CAPD that was done using a single tubing set was simple and less costly. However, the high infection rate associated with CAPD made it less attractive. The other shortcoming of CAPD is the fact that once on CAPD, a patient is committed to perform 4 or more fluid exchanges per day, every day. Each fluid exchange may take as much as one hour. Consequently patient "fatigue", which leads to poor aseptic dialysis technique and a high infection rate, is very common. Hence CCPD was introduced as an alternate modality. The limitations of the CCPD programme (machine and tubing complexities, higher cost of tubing sets, non-portable equipment etc.) did not make it easy for most patients to consider CCPD as a better alternative to CAPD.